There is a case where plural computers and peripheral devices thereof are connected to each other and they are used. In this case, it is demanded to manage the power supply of each device efficiently.
A document 1 (Japanese Laid-Open Patent Publication No. 2004-259030) discloses a power supply controlling apparatus that supplies an electric power to plural devices, and switches a power supply on or off for each device. A document 2 (Japanese Laid-Open Patent Publication No. 62-500269) discloses a power supply controlling system that includes a master power supply controlling apparatus controlling the system, and a slave power supply controlling apparatus controlled by the master power supply controlling apparatus. A document 3 (Japanese Laid-Open Patent Publication No. 2002-73221) discloses a system that includes plural uninterruptible power supply units supplying an electric power, and a control device executing supervisor control.
However, when an controller in the above-mentioned apparatus or the above-mentioned system, and the master power supply controlling apparatus are lost, the power supply cannot be efficiently managed.